Mosquito borne diseases: Malaria, Japanese encephalitis (JE) and filariasis are the most important mosquito borne diseases prevalent in the north-eastern states. North-eastern region of India though contributes to about 3.7% Indian population yet shares 8-10% of all malaria cases and 13-15% malaria deaths reported in the country putting severe burden on the economy of the region. Predominantly Plasmodium falciparum malaria (~80%), highly endemic in hills, foothills and forest areas of NE India, is chiefly maintained by Anopheles dirus complex and An. minimus complex mosquitoes. Japanese encephalitis is endemic in Assam (Dibrugarh, North Lakhimpur, Sibsagar, Jorhat and Sonitpur highly endemic districts) with annual average morbidity of about 300 cases and ~ 41% case fatality rate. Bancroftian filariasis disease, transmitted by Culex quinquefasciatus mosquitoes, is overwhelmingly concentrated in tea garden populations of Assam with an estimate of 0.36 million microfilaraemia carriers and 90,000 clinical cases.

Drug abuse and HIV/AIDS: North-eastern region of India, being in close proximity to the Golden Triangle, faces illegal drug trafficking and drug abuse problem in an acute manner. There is a gradient with higher prevalence of drug abuse in international bordering north-eastern states, thus, Manipur leading the region with approximately 11 drug users per 1000 population. Injecting the drug is the most common form of drug abuse in Manipur, Mizoram and Nagaland. The National AIDS Control Organization reports a seropositivity rate of 7.7 per thousand in sero-surveillance of high risk groups and general population estimates of 1.7 per thousand in India. Transmission of HIV in north-eastern region is mainly associated with the injecting drug abuse. Opium, alcohol and tobacco are other commonly abused substances in NE region.

Trematode infections: Food borne trematode infections and schistosomal dermatitis are public health concerns in north-eastern region of India. Due to the peculiar food habits of different ethnic groups in north-east India, especially eating raw/poorly cooked crabs, pulmonary paragonimiasis is widely prevalent in this region. Caused by the Paragonimus, the lung fluke, pulmonary paragonimiasis disease mimics the symptoms of pulmonary tuberculosis causing a diagnostic dilemma to the treating physicians. At least 7 trematodes have been found to cause human infections in this region. Recently non-human schistosomes like Schistosoma spindale, S. nasale and occulate schistosomes have been incriminated as the causative organisms of paddy field dermatitis, a serious occupational disease putting millions of agricultural labourers at risk, in Assam.

Haemoglobinopathies: As per an estimate there might be about 45 million carriers and about 15,000 infants are born each year with haemoglobinopathies in India. The carrier frequency of haemoglobinopathies varies from 3 to 17% while cumulative gene frequency of three most predominant abnormal haemoglobinopathies i.e. sickle cell, Hb D and Hb E has been estimated to be 5.4% in different population groups of India. In north-east India, especially Assam, high prevalence of (20-60%) of Hb E, the most common haemoglobin variant among the local inhabitants belonging to Mongoloid ethnic stock, and Hb S among the immigrant tea garden labour population has been reported.

Cancers: In north-eastern region of India, cancer of nasopharynx (NPC) has been found to be highest in the country i.e. 1% of total carcinoma cases as compared to all India average of 0.6%. Within the region, 55% of total NPC cases are reported from Nagaland followed by Manipur (22.1%). Cancer of oesophagus, the highest reported (11.2% of all cancers in NE region) and cancer of stomach are prevalent cancers in Assam and Mizoram respectively.

Hypertension and Coronary Heart Disease: All India prevalence pattern shows that in urban population prevalence of hypertension is 6.5% while in rural population it is 3.6%; prevalence of CHD in urban and rural populations is 5.7% and 2.1% respectively. An uneven prevalence of hypertension has been reported in various population groups in north-east India. While Mizos have less prevalence of hypertension, it is very high in tea garden population in Assam and is in between in indigenous Assamese population.

Medicinal plants of NE India: North-east India is very rich in floral diversity and is one among the three hot spots of bio-diversity in India. Many ethnic groups of North-eastern region practice their traditional system of medicine, mostly relying on indigenous plants for curing various ailments. The medicinal properties of locally available plants need authentic documentation and scientific verification.